Pink seas

Local Australian press has been reporting a large algal boom and the consequent closure of beaches for a few days. The bloom has grown large enough that news has now reached the international media. AFP reports:

The algae, noctiluca scintillans, forced the closure of Sydney’s Bondi beach and a number of neighbouring inlets earlier this week, and government officials said it had now spread along the fringes of two states.

“Samples taken at Bondi Beach on 27 November confirmed the presence of noctiluca scintillans, which appears as a pinkish to reddish discolouration in water,” the New South Wales government’s water office said.

“It can also appear to be phosphorescent at night.”

Aerial footage shot over neighbouring Victoria state showed huge blooms of the oily pink scum off Bells Beach, a popular surfing spot, and Lorne, south of Melbourne.

Some keen surfers were seen paddling undeterred through the muck, which has a fishy odour and can irritate the skin and eyes but is not dangerous to humans.

Fisherman were advised not to eat anything caught in an affected area as a precaution.

“There are no practical options for treating marine algal blooms,” said Peter Codd from Victoria’s department of sustainability and environment.

A year ago the Hindu had reported the increasing frequency of algal blooms in Indian littoral waters, and the consequent dangers:

Harmful algal blooms (HAB), lethal for human beings and marine ecosystems alike, are steadily increasing in intensity in the Indian waters. Researchers have found out that the toxic blooms had increased by around 15 per cent over the last 12 years in Indian seas.

There were 80 harmful blooms between 1998 and 2010 in the Indian seas against the 38 that took place between 1958 and 1997. The number of such blooms was just 12 between 1917 and 1957, according to scientists.
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The first recorded observation on algal blooms in India was in 1908.

The blooms turn lethal for human beings when they consume marine organisms that feed on such algae. Incidents of paralytic shell fish poisoning, following an algal bloom, was reported in 1981 from Tamil Nadu, Karnataka and Maharashtra. Three persons lost their lives and 85 were hospitalised in Tamil Nadu.

In a similar incident at Vizhinjam in Kerala in 1997, seven persons died and around 500 were hospitalised. These people had consumed a mussel, which had fed on toxic algae. Another bloom that hit Kerala in 2004 resulted in nauseating smell emanating from the coastal waters extending from Kollam to Vizhinjam. More than 200 persons suffered from nausea and breathlessness for short duration due to the foul smell. The bloom also resulted in massive death in the region, scientists said.
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It was the Arabian Sea that experienced the most number of blooms over the decades. The Bay of Bengal recorded blooms by and large during the northeast monsoon when cyclonic storms occurred in the region. Global warming and the resultant storminess could also influence the frequency of bloom formation in the Indian seas, scientists said.